There have been many different types of air compressors developed over the decades for particular uses and applications, with design considerations being tailored to each particular application. Without chronicling the developmental history of the various types of air compressors, recent developments in fuel injection systems for internal combustion engines have created a need for a compact, high pressure, low volume air compressor that reliably operates over an extended range of operating speed. Such an air compressor is particularly useful for such a fuel injection system that is used on 2-cycle engines, such as outboard motors and the like, which generate substantial horsepower even though the engines are of relatively small size. Because of the relatively small size of the engine itself, the air compressor which is driven by the engine must occupy a relatively small volume and yet produce high pressure at operating speeds experienced during cranking during starting and from idle to full throttle speed.
Accordingly, it is a primary object of the present invention to provide an improved air compressor which has the capability of providing high output pressure with reasonable output volume at varying operating speeds, and which is reliable in its operation over such varying operating speeds.
Yet another object of the present invention is to provide such an improved air compressor which exhibits reliable operation and which is lubricated and also water cooled.
Another object of the present invention is to provide such an improved air compressor which utilizes a reciprocating piston connected to a crankshaft assembly by a connecting rod and which utilizes a side inlet for air that is to be compressed and has a reed valve at the output thereof which is covered by a cylinder head and defines a relatively small output chamber that acts to reduce the amplitude of the pressure spikes that are produced by the reciprocating piston.
A related object lies in the provision of a tube connected to the output chamber for providing an increased volume which acts as an accumulator for the compressed air.
Another object lies in the provision of the crankcase being pressurized and operating to provide an auxiliary pressure source, albeit at lower pressure levels, for driving other devices associated with the engine, such as a low pressure fuel pump or the like.
Still another object of the present invention is to provide a power take-off connected to the crankshaft of the compressor for driving other auxiliary devices of the engine to which the air compressor is attached, such as power steering.
Another object of the present invention is to provide a sophisticated oil lubrication system for the compressor and particularly the piston thereof, which includes multiple piston rings, including an oil communicating piston ring and piston that operate to recover the lubricating oil between the cylinder wall and the piston.
A related object of the present invention lies in the provision of controlling the oil that is admitted into and removed from the crankcase during operation, particularly in light of the pressures that are developed within the crankcase which would otherwise disrupt the normal flow of oil into and out of the crankcase.
Yet another object of the present invention is to provide an improved air compressor which is compact and of superior design and which includes a simple and effective means in which to secure the crankshaft assembly within the crankcase, which enables easy insertion and removal.